Unscrewing device for pipe-joints



C. R. EDWARDS.

UNSCREWING DEVICE FOR PIPE JOINTS.

APPLICATION FILED AUG.41 |919.

C. R. EDWARDS. UNSCREWING DEVICE FOR PIPE JOINTS.

APPLIcATxoN FILED AuG.4. |919.

1,334,487. Patented Mm=.23,1920.

2 SHEETS-SHEET 2.

pivoted at-opposing points to the inner wall of the section 1. Theoperative faces of said dogs are serrated so as to more readily engagewith the casing or the wall ofthe bore.

The lower end of the section 2 is reduced forming the outwardly threadedneck 23,

-which may beyscrewed directly into the section of pipe to be backed offor unscrewed or which may receive a fishing tool o-f any conventionalform for engagement with the pipe.

The device is"iirst attached to a string of pipe whose sections areconnected by means of collars having right hand threads, and

cated by the arrows i-n Fig. 2. The section 2 will be temporarily heldagainst rotation, during this movement, on account of its friction withthe section of pipe upon which it is resting, and the section 1 will beheld against rotation by reason of its friction with the section 2. Thelsection 1, being -thus held, will cause the spur gears 16 to travelaround the rack face 17 in the direction indicated by the arrows in Fig.3, thus forcing the levers 21 and the dogs 22 outwardly through the wideslots 24, 24, which are cut through opposing sides of the section l,causing the dogsv22, 22, to engage with the casing wall, or in theabsence of casing, with the walls of the bore, and the section 1V willthus be firmly held against rotation in the bore. A continued rotationof the shaft 6 will be transmitted through the spur gears 16 and 19 andthe shafts 15 to the section 2, turning it in the opposite or left handdirection and causing the same to engage with the adjacent section ofthe drill stem and rotate the same backwardly, thus unscrewing the samefrom the sections underneath and when unscrewed, the same may. bewithdrawn from the bore.

What I claim is:

1.- A device for unscrewing pipe in a well bore, including twoindependently rotatable members, a drlving shaft, means operatively`connecting said shaft with one of said member and actuated by saidmeans into engage- `ment v'with the walls of the bore, whereby said lastmentioned member is anchored against rotation.

2. A device for unscrewing pipe in a well bore, including an inolosedcaslng formed of two independently rotatable sections, a driving shafthaving-bearings in said sections, means operatively connecting saidtation.

3f A device for unscrewing pipe in a well bore, including a casingformed of two independently rotatable sections, a driving shaft,extending through the casing and having bearings in the respectivesections thereof, engaging members carried by one of said sections,means operatively connecting said shaft with said engaging members andwith the other section, said means being actuated by said shaft to forcesaid members into engagement with the walls of the bore wherebythe-first mentioned section is anchored against rotation, and thecontinued rotation of said shaft thereafter operating through said meansto rotate the other section reversely with respect to the directio ofthe rotation of said shaft:

` 4. A device for unscrewing pipe in a well bore, including a casingformed of two independently rotatable sections, a Vdriving shaftextending through the casing, engaging dogs carried by one section ofthe easing, means operatively connecting said shaft with said dogswhereby the rotation of the shaft relative to the casing will actuatesaid y dogs into engagement with the well bore,

thereby anchoring said section against rotation, said means being alsooperatively connected wlth the other sectlon and operating through theshaft to drive the other section of the casing, reversely lwith respectto the shafts rotation when said first mentioned section is anchoredagainst rotation. In testimony whereof he has signed his name to thisspecification in the presence of two subscribing witnesses.

CHI-IARLES R. EDWARDS. Witnesses IRENE I. BRUNs, ELLIE MESCHKAT.

